..for what it is worth..i was getting horrible ignition whine on my system...until i installed along with the Rio my old head unit and used the AUX inputs. Whine gone!! it seems that whenever i touched the RCA inputs of the AUX the whine would jump out! further..as they were laying on top of all the wires in the dash they were picking up all kinds of ignition noise. now that i have the rca plugs of my other unit plugged ito them they are now grounded and pick up absolutely no noise!!!

so..if you cant seem to rid your system of unwanted noise, take a look at these inputs and ground them if you can...very happy now!!